A golf club head having a viscoelastic body has been proposed to improve the hitting impression or adjust the hitting sound on impact. When the viscoelastic body is attached, the vibration on impact is absorbed by the viscoelastic body to improve the hitting impression and decrease the hitting sound that is offensive to the player's ear. Japanese Utility Model Registration No. 3112038 discloses a golf club head having a plurality of types of elastic weights having different specific gravities and elasticities. Japanese Patent Laid-Open No. 2004-313777 discloses a golf club head having a plurality of types of elastic bodies having different hardnesses.
The present inventors inspected the resonance frequency of a golf club head alone. A plurality of resonance frequencies were confirmed in a range of approximately 4,000 Hz to 10,000 Hz. Therefore, to reduce the vibration of the golf club head effectively, it is desired to attach a viscoelastic body that can reduce the vibration within a wide frequency range to the golf club head. In general, however, there is a limit to the frequency range of a viscoelastic material that is effective to reduce vibration depending on the material. The present inventors also inspected the resonance frequency of the golf club as a whole. A plurality of resonance frequencies were confirmed in a range of approximately 2,000 Hz or less. Therefore, to reduce the vibration of the golf club as a whole, the vibration is preferably reduced within a wider frequency range.